Method for forming a directional mesh

ABSTRACT

Woven structures and associated systems for weaving such structures are disclosed. Some disclosed innovations pertain to braided structures, such as braided wire structures, with axially asymmetric woven structures (or “directional meshes”) being examples. Other innovations disclosed herein pertain to methods of manufacturing woven structures, with automated methods of braiding directional meshes being examples. Some directional mesh embodiments can be configured and used as energizable electrodes for electrosurgical therapies, for example, bipolar vaporization therapies.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/155,233, filed on Jan. 14, 2014, now U.S. Pat. No. 10,260,181, whichclaims the benefit of and priority to U.S. Provisional Application Ser.No. 61/752,314, filed Jan. 14, 2013, the contents of which are herebyincorporated by reference as if recited in full herein for all purposes.

BACKGROUND

The innovations and related subject matter disclosed herein(collectively referred to as the “disclosure”) generally pertain towoven structures and associated systems for weaving such structures.Some aspects of disclosed innovations pertain to braided structures,such as braided wire structures, with a braided directional mesh beingbut one example. Other aspects of innovations disclosed herein pertainto methods of manufacturing woven structures, with an automated methodof braiding a directional mesh being but one example. As but oneexample, some disclosed directional mesh structures constitute a portionof an energizable electrode configured for an electrosurgical therapy.

As used herein, the term “directional mesh” means an axially asymmetricwoven structure. The sequence of drawings in FIGS. 1A, 1B and 1C shows aworking embodiment of an innovative directional mesh.

Transurethral resection of the prostate (TURP) has been considered thereference ‘gold standard’ surgical procedure for low urinary tractsymptoms (LUTS) due to benign prostatic hyperplasia (BPH). The highsuccess rate of TURP as measured by substantial and sustainedimprovements of symptom scores, urinary flow rate and other functionalparameters, remains associated with significant morbidity.

As a consequence, a number of minimally invasive therapeuticalternatives have been proposed during the last 30 years, including,inter alia, bipolar vaporization. Bipolar vaporization has shown promiseas being an effective, safe and low-cost minimally invasive technique,providing very good hemostasis control and low complication rates.Suitable surgeon vision and hemostasis available during a bipolarvaporization procedure makes bipolar vaporization suitable for use inpatients from high-risk groups, including those with cardiac pacemakers,bleeding disorders, or under anticoagulant therapy. Together with arelatively lower-cost per procedure compared to laser techniques, suchadvantages make bipolar vaporization an attractive technique for use ina variety of urological practice settings.

Bipolar vaporization techniques generate little heating of tissuesurrounding a treatment site and are conducted without direct contact totissue at a treatment site. In general, a bipolar electrode generates athin plasma layer surrounding an electrically conductive portion of theelectrode when an electrical current passes through the conductiveportion. The plasma can vaporize a relatively thin layer of tissue at atreatment site on or in a patient's body without excessive heating (orother detrimental effect) of surrounding tissue.

To date, energizable electrodes have not allowed adjustments to theirconfiguration during use. Nonetheless, an energizable electrode havingan adjustable configuration can provide a surgeon with a variety oftherapeutic options without having to replace or substitute oneenergizable electrode for another electrode having a differentconfiguration.

Accordingly, there remains a need for an energizable electrode having anadjustable configuration. For example, there remains a need for anenergizable electrode having a very compact profile to ease deploymentof the electrode to a treatment site, being configured to expand tocover a relatively large area when deployed at or near the treatmentsite, and being further configured to contract to the compact profilefor removal from the treatment site.

SUMMARY

The innovations disclosed herein overcome many problems in the prior artand address the aforementioned as well as other needs. By way ofexample, woven structures and associated systems for weaving suchstructures are disclosed. Some disclosed innovations pertain to braidedstructures, such as braided wire structures, with axially asymmetricwoven structures (or “directional meshes”) being examples. Otherinnovations disclosed herein pertain to methods of manufacturing wovenstructures, with automated methods of braiding directional meshes beingexamples. Some directional mesh embodiments can be configured and usedas energizable electrodes for electrosurgical therapies, for example,bipolar vaporization therapies.

According to a first innovative aspect, woven constructs are disclosed.A woven construct can include a plurality of interwoven wires definingan operative segment. The operative segment can have a longitudinalaxis. Positioned radially outwardly of the longitudinal axis, theoperative segment can have a region of relatively higher wire-densityand a region of relatively lower density. The operative segment can be abraided directional mesh.

In some embodiments, the region of relatively higher wire-density andthe region of relatively lower wire-density are asymmetricallypositioned relative to the longitudinal axis. Such a configuration canallow the operative segment to buckle in a predetermined direction undera sufficient, longitudinally compressive load applied to the operativesegment. As but one example, the predetermined direction can besubstantially radially outward relative to the longitudinal axis.

In some embodiments the plurality of wires can also define opposed endportions, with the operative segment being positioned between theopposed end portions. A wire-pitch of the operative segment can besubstantially lower than a wire-pitch of one or both of the opposed endportions.

Each of the wires can extend substantially helically around thelongitudinal axis by between about 120 degrees and about 240 degrees,such as, for example, by between about 150 degrees and about 210degrees.

The operative segment can be configured to generate a suitable plasmafield for an electrosurgical therapy when a sufficient electricalcurrent passes through the plurality of interwoven wires.

According to another aspect, braiding machines are disclosed. Forexample, a braiding machine can be configured to so interweave aplurality of wires as to define a braided directional mesh.

Such a braiding machine can be configured to vary a longitudinal pitchof the interwoven wires. For example, a first segment of the braideddirectional mesh can have a corresponding first longitudinal pitch and asecond segment of the braided directional mesh can have a correspondingsecond longitudinal pitch being relatively higher than the firstlongitudinal pitch.

In some embodiments, a braiding machine can have a first plurality ofwire carriers configured to orbit about a portion of the braidingmachine in a first orbital direction, and a second plurality of wirecarriers configured to orbit about the portion of the braiding machinein a second orbital direction generally opposite to the first orbitaldirection. Such a braiding machine can also be configured to interweaveeach wire carrier in the first plurality of wire carriers with each wirecarrier in the second plurality of wire carriers to interweave theplurality of wires.

In a general sense, the first plurality of wire carriers can include nwire carriers, and the second plurality of wire carriers can include mwire carriers. At least one and fewer than all of the n wire carrierscan be populated with a supply of wire. At least one and fewer than allof the m wire carriers can be populated with a supply of wire. Such abraiding machine configuration can as symmetrically interweave theplurality of wires.

In some embodiments, the supply of wire can include a bobbin containinga corresponding spool of wire, and the corresponding plurality of spoolsof wire can constitute the plurality of wires.

According to yet another aspect, methods of forming a directional meshare disclosed. For example, such a method can include axiallyasymmetrically interweaving each of a first plurality of wires with eachof a second plurality of wires.

According to some disclosed methods, the first plurality of wires can besubstantially helically wound in a first direction around a longitudinalaxis, and the second plurality of wires can be substantially helicallywound in a second direction around the longitudinal axis. Acircumferential component of the first direction relative to thelongitudinal axis can be substantially opposite a circumferentialcomponent of the second direction relative to the longitudinal axis. Alongitudinal component of the first direction relative to thelongitudinal axis can be substantially identical to a longitudinalcomponent of the second direction relative to the longitudinal axis.

According to some disclosed methods, a region of relatively higherwire-density can circumferentially oppose, relative to the longitudinalaxis, a region of relatively lower wire density. The region ofrelatively higher wire-density and the region of relatively lowerwire-density can be configured such that the woven first and secondpluralities of wires are configured to buckle in a predetermineddirection under a sufficient, longitudinally compressive load.

According to some disclosed methods, an operative segment can be formedbetween opposed end segments. The operative segment can have arelatively lower pitch than either of the opposed end segments. In theoperative segment, each of the plurality of wires can extendsubstantially helically around the longitudinal axis by between about120 degrees and about 240 degrees, with between about 150 degrees andabout 210 degrees being but one example of a suitable range of winding.

According to some disclosed methods, a directional mesh can beconfigured to generate a suitable plasma field for an electrosurgicaltherapy when a sufficient electrical current passes through theplurality of interwoven wires.

According to some disclosed methods, a longitudinal pitch of theinterwoven wires can be varied. For example, a first segment of thedirectional mesh can have a corresponding first longitudinal pitch, anda second segment of the directional mesh can have a corresponding secondlongitudinal pitch being relatively higher than the first longitudinalpitch.

According to some methods, the act of interweaving each of the firstplurality of wires with each of the second plurality of wires caninclude orbiting a first plurality of wire carriers about an orbitalcenter in a first orbital direction and orbiting a second plurality ofwire carriers about the orbital center in a second orbital direction.The second orbital direction can be in a direction generally opposite tothe first orbital direction.

According to some methods, the first plurality of wire carriers caninclude n wire carriers and the second plurality of wire carriers caninclude m wire carriers. At least one and fewer than all of the n wirecarriers can be populated. At least one and fewer than all of the m wirecarriers can be populated. Each populated wire carrier can include abobbin containing a corresponding spool of wire. A given plurality ofspools of wire can constitute a respective plurality of wires.

The foregoing is not intended to be an exhaustive list of embodimentsand features of the inventive subject matter. The appended claims, asoriginally filed in this document, or as subsequently amended, arehereby incorporated into this Summary section as if written directly in.Persons skilled in the art are capable of appreciating other embodimentsand features from the following detailed description in conjunction withthe drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Unless specified otherwise, the accompanying drawings illustrate aspectsof the innovative subject matter described herein.

FIGS. 1A, 1B and 1C form a sequence of drawings showing a workingembodiment of a directional mesh.

FIG. 2 shows an isometric view of an example of a woven structure of thetype disclosed herein.

FIG. 3 shows a schematic illustration of a braiding machineconfiguration suitable for manufacturing a directional mesh.

FIGS. 4A, 4B, 4C and 4D schematically illustrate a sequence of braidingmachine configurations during a braiding process.

FIGS. 5A, 5B, 5C and 5D schematically illustrate a sequence of braidingmachine configurations during a directional mesh braiding process.

FIGS. 6A and 6B are drawings of a working embodiment of a braidingmachine as described herein. FIG. 6B shows a carrier populated with abobbing having a spool of wire.

FIG. 7 is a drawing of an unpopulated carrier separate from and suitablefor use with a braiding machine as shown in FIG. 6A.

DETAILED DESCRIPTION

The following describes various principles related to woven structuresand associated systems by way of reference to specific examples ofbraided structures and associated systems. In some innovativeembodiments, a directional mesh constitutes a portion of an energizableelectrode configured for electrosurgical therapy.

One or more of the principles can be incorporated in various systemconfigurations to achieve any of a variety of system characteristics.Systems described in relation to particular configurations,applications, or uses, are merely examples of systems incorporating theinnovative principles disclosed herein and are used to illustrate one ormore innovative aspects of the disclosed principles. Accordingly, wovenstructures and associated systems having attributes differing from thosespecific examples discussed herein can embody one or more of theinnovative principles. Accordingly, such alternative embodiments alsofall within the scope and spirit of this disclosure.

Overview

An innovative woven structure can have an axial asymmetry or othercharacteristic adapted to cause the structure to buckle asymmetricallywhen sufficiently compressed axially. The sequence of drawings shown inFIGS. 1A, 18 and 1C illustrate a specific example of asymmetric bucklingof a braided wire mesh.

As shown in FIG. 1A, the undeformed mesh 100 is axially asymmetric,having a region 105 of relatively higher wire density positionedcircumferentially opposite a region 110 of relatively lower wiredensity. When longitudinally axially compressed sufficiently to buckle,the mesh 100 expands in a circumferentially asymmetric manner to form abulge 115 extending radially outwardly of the longitudinal axis 120.Such a mesh is sometimes referred to as having a “directional” propertyinsofar as the mesh 100 expands in generally one direction, as opposedto a circumferentially symmetric mesh that would tend to expanduniformly relative to the circumference, e.g., radially outward in alldirections.

The directional mesh shown in FIGS. 1A, 1B, and 1C is configured as anenergizable, bipolar electrode suitable for use in providing anelectrosurgical therapy. The pictured directional mesh defines anoperative segment 125 of the energizable electrode and is configured toextend between and electrically couple with opposed electrodes 130 a, b.The opposed electrodes, in turn, are configured to urge toward eachother and thereby apply a longitudinally compressive load to theoperative segment 125. Such an electrode configuration can permit asurgeon to tailor the electrode configuration in situ to suit a giventherapy without having to withdraw the electrode from a treatment site.

In some embodiments, a catheter or other electrosurgical device used incombination with disclosed energizable electrodes can be configured tolimit the extent of longitudinal compressive or tensile displacement.Such a configuration can help ensure that the maximum stress within theenergizable electrode remains sufficiently below the respectivematerial's yield strength.

Woven Constructs

As shown in FIG. 2, a woven construct 200 can be formed from a pluralityof interwoven, biocompatible, electrically conductive wires 201 definingan operative segment 225 positioned between opposed end segments 231 a,b. The operative segment 225 has a longitudinal axis (not shown).Positioned radially outwardly of the longitudinal axis, the operativesegment 225 defines a region 205 of relatively higher wire-density and aregion 210 of relatively lower density, similar to the workingembodiment 100 pictured in FIGS. 1A, 1B, and 1C.

Some disclosed energizable electrodes can be formed from a materialhaving relatively high yield strength to permit the energizableelectrode to change configurations without undergoing a plasticdeformation. For example, some suitable materials can elastically deformbetween a compact configuration suitable for deploying the electrode(e.g., shown in FIG. 1A) and an expanded configuration (e.g., shown inFIG. 1C) suitable for electrosurgical therapies.

As but several examples, suitable materials for innovativeelectrosurgical electrodes can include an alloy of stainless steel,copper beryllium or platinum iridium. In some embodiments, a suitablewire can have a diameter of between about 0.005 inch and about 0.007inch (inclusive). Well-suited materials for electrosurgical applicationsexhibit durability under repetitive cycles of energization andde-energization with RF electrical energy. As but one particular, butnot exclusive, example, platinum can be well-suited for electrosurgicalapplications.

For applications that do not require electrical energization,high-strength polymer materials can be suitable. As an example, Kevlarcan be a suitable material.

The region 205 of relatively higher wire-density and the region 210 ofrelatively lower wire-density are asymmetrically positioned relative tothe longitudinal axis. Such a configuration permits the operativesegment 225 to buckle in a predetermined direction under a sufficient,longitudinally compressive load applied to the operative segment. Asshown in the sequence of drawings in FIGS. 1A, 1B, and 1C, thepredetermined direction can be substantially radially outward relativeto the longitudinal axis (e.g., axis 120).

As shown in FIG. 2, a wire-pitch of the operative segment 225 issubstantially lower than a wire-pitch of one or both of the opposed endportions 231 a, b. As used herein, “wire-pitch” refers to a ratio of ameasure of a given wire's circumferential winding to a measure oflength. In some instances, the measure of length can be measuredrelative to the resulting construct (e.g., a directional mesh 100, 200)and in other instances the measure of length can be measured relative tothe wire (e.g., a length of the wire 201). As but one example, a givenwire-pitch of a wire extending about half-way around a longitudinal axisin one centimeter could be 0.5 windings per centimeter. Another,relatively higher wire-pitch could be 2 windings per centimeter.

In a general sense, regions of a woven construct 200 outside theoperative segment 225 can be woven to a suitably high pitch (e.g.,approaching a “solid tubular” construct). As but one example, a 0.041inch mandrel was used to weave a 0.005 inch diameter wire at a pitch ofabout 130 windings per inch (PPI) (e.g., between about 120 PPI and about140 PPI) for regions outside of the operative segment 225. In contrast,the operative segment 225 was woven at about 1-3 PPI over a distance ofbetween about 0.3 inch to about 0.4 inch. A woven construct 200 caninclude a plurality of operative segments 225 juxtaposed with acorresponding plurality of outside regions 231 a, b. Each outside region231 a, b of the woven construct 200 can be cut to separate individualenergizable electrodes from the woven construct 200. The outside regions231 a, b can be trimmed to a selected length.

As shown in FIG. 2, each of the wires 201 extends substantiallyhelically around the longitudinal axis, though each wire is interwovenwith several other wires causing the wires to depart slightly from apure helical winding. In the operative segment 225, the wires extendcircumferentially around the longitudinal axis by about 180 degrees, forexample between about 120 degrees and about 240 degrees, such as betweenabout 150 degrees and about 210 degrees. Stated differently, a distalend of a given helical wire 201 in the operative segment 225 iscircumferentially offset from the corresponding proximal end by about180 degrees, for example between about 120 degrees and about 240degrees, such as between about 150 degrees and about 210 degrees.

Interweaving

A directional mesh can be formed by axially asymmetrically interweavingeach of a first plurality of wires 201 with each of a second pluralityof wires 201.

For example, as shown schematically in the sequence of illustrations inFIGS. 4A, 4B, 4C and 4D, a braiding machine 10 can interweave each of afirst plurality of wires (or wire carriers, for example, bobbins havingrespective spools of wire) 13 a with each of a second plurality of wires(or wire carriers, for example, bobbins having respective spools ofwire) 13 b. In particular, the braiding machine 10 has a platen 11having a bi-directional track 12 a, 12 b configured to urge the firstplurality of wires 13 a generally clockwise through a nominal orbit 16relative to the platen 11 and to urge the second plurality of wires 13 bgenerally counter-clockwise through the nominal orbit 16.

In the example shown in FIGS. 4A, 4B, 4C and 4D, the orbital pathsdefined by the tracks 12 a, 12 b oscillate radially relative to theplaten 11 about the nominal orbit 16. The tracks 12 a and 12 b intersectat, for example, intersection 12 c. The bi-directional track 12 a, 12 bcauses the wires 13 a to interweave with the wires 13 b as the wires 13a, 13 b travel through their respective orbital paths. Motion of thewires 13 a, 13 b along each portion of the tracks 12 a, 12 b isindicated by the arrows 14 a, 14 b. FIG. 4B shows an intermediateconfiguration of a braiding machine 10, as well as relative positions offirst and second pluralities of wires 13 a, 13 b, after each rotatableportion of the bi-directional track 12 a, 12 b has advanced by about 90degrees relative to the position shown in FIG. 4A. FIG. 4C shows thebraiding machine 10 and wires 13 a, 13 b after the bi-directional track12 a, 12 b has advanced by about 90 degrees relative to the positionshown in FIG. 4B. FIG. 4D shows the braiding machine 10 and wires 13 a,13 b after the bi-directional tracks 12 a, 12 b have advanced by about90 degrees relative to the position shown in FIG. 4C. As the wires 13 a,13 b pass through their respective counter-directional orbits, theinterweaving of the wires 13 a, 13 b forms a woven construct adjacent anorbital center, similar to woven ribbons wound about a maypole.

As noted above in relation to FIGS. 4A, 4B, 4C and 4D, some braidingmachines 10 interweave first and second pluralities of spools of wire 13a, 13 b. More particularly, some braiding machines 10 are configured towithdraw a woven construct from the orbital center of the platen 11(e.g., in a direction generally perpendicular to the platen 11).

Wire-pitch of a woven construct formed using an approach as summarizedabove is proportional to orbital speed (e.g., number of orbits per unitof time) of the wires (or carriers) 13 a, 13 b and inverselyproportional to a speed at which the woven construct is withdrawn, e.g.,from the braiding machine. Accordingly, if a rate at which the wovenconstruct is withdrawn increases and the orbital speed of the wires 13a, 13 b remains constant, the resulting construct will have a relativelylower wire-pitch. Conversely, if a rate at which the woven construct iswithdrawn decreases and the orbital speed of the wires 13 a, 13 bremains constant, the resulting construct will have a relatively higherwire-pitch. Thus, the construct shown in FIG. 2 can be formed bywithdrawing the construct at a relatively lower rate while the endsegments 231 a, b are being woven, and withdrawing the construct at arelatively higher rate while the operative segment 225 is being woven.

The mesh design and the set-up of the braider to produce the designenable the directional mesh shown in FIGS. 1A-C and 2 to be made in acontinuous process on a multi-carrier braiding machine as depicted inFIGS. 4A-D, 5A-D and 6. For example, a continuous woven construct cancomprise a plurality of operative segments 225 juxtaposed with aplurality of end segments 231 a, b. The continuous woven construct canbe segmented (e.g., each end segment 231 a, b can be bisected to formone woven construct 200 having an operative segment 225 positionedbetween opposed end segments 231 a, b, as shown in FIG. 2.)

Withdrawing a woven construct formed from the orbiting wires (orcarriers) 13 a, 13 b can cause the first plurality of wires 13 a to besubstantially helically wound in a first direction around a longitudinalaxis, and the second plurality of wires to be substantially helicallywound in a second direction around the longitudinal axis. With thecounter-orbits described above, a circumferential component of the firstdirection relative to the longitudinal axis is substantially opposite acircumferential component of the second direction relative to thelongitudinal axis, while a longitudinal component of the first directionrelative to the longitudinal axis is substantially identical to alongitudinal component of the second direction relative to thelongitudinal axis.

An asymmetrically loaded braiding machine 10, as shown in FIGS. 5A-D caninterweave a plurality of wires to define a braided directional mesh ofthe type shown in FIGS. 1A, 1B, 1C, 1 d and 2. In particular, operatingan asymmetrically loaded braiding machine can form a woven constructhaving a region of relatively higher wire-density circumferentiallyopposing, relative to a longitudinal axis, a region of relatively lowerwire density.

For example, as shown in FIGS. 3, 4A, 4B, 4C, and 4D, a braiding machine10 can have 16 wire carriers, with 8 wire carriers configured to orbitgenerally in a clockwise direction relative to the platen 11 and 8 wirecarriers configured to orbit generally in a counter-clockwise directionrelative to the platen 11. In FIGS. 3 and 5A, 5B, 5C and 5D, fewer thanall available wire carriers (and at least one carrier corresponding toeach orbital direction) populate the platen 11 asymmetrically.

For example, in FIG. 3, several populated wire carriers, R, configuredto orbit in a generally clockwise direction relative to the platen 11are juxtaposed with unpopulated wire carriers configured to orbit in thesame direction. Similarly, several populated wire carriers, L,configured to orbit in a generally counter-clockwise direction relativeto the platen 11 are juxtaposed with unpopulated wire carriersconfigured to orbit in the same direction. The asymmetry is introducedinsofar as a populated carrier R is positioned adjacent a populatedcarrier L, and counter-orbiting, unpopulated carriers 11 a, b arepositioned adjacent to each other. Such an asymmetric loading of abraiding machine can form a directional mesh construct as shown in FIGS.1A, 1B, 1C and 2.

Although 16-carrier braiding machines have been described by way ofexample, above, similar principles apply to any braiding machine havinga first plurality of wire carriers configured to interweave with acounter-orbiting second plurality of wire carriers. For example, thefirst plurality of wire carriers can include n wire carriers and thesecond plurality of wire carriers can include m wire carriers. At leastone and fewer than all of the n wire carriers can be populated, and atleast one and fewer than all of the m wire carriers can be populated,and the braiding machine can thereby be configured to asymmetricallyinterweave the first plurality of wire carriers with the secondplurality of wire carriers to form a directional mesh.

Other Exemplary Embodiments

The embodiments described above generally concern woven structuresconfigured to buckle in a predetermined direction. Nonetheless, otherembodiments are possible. For example, a coil spring can be bowedoutwardly. Such a coil spring can, in some embodiments, have alongitudinally variable coil pitch (e.g., a segment of the spring can beplastically deformed, or “stretched,” to impart the segment with arelatively lower pitch). A region of relatively lower pitch can be urgedtogether to bow outwardly. In another alternative embodiment, one ormore apertures can be cut into a tubular metal structure (e.g., by lasercutting), defining a segment of the tubular metal structure configuredto buckle in a predetermined direction under a longitudinallycompressive load.

This disclosure references the accompanying drawings, which form a parthereof, wherein like numerals designate like parts throughout. Thedrawings illustrate specific embodiments, but other embodiments may beformed and structural and logical changes may be made without departingfrom the intended scope of this disclosure.

Directions and references (e.g., up, down, top, bottom, left, right,rearward, forward, etc.) may be used to facilitate discussion of thedrawings but are not intended to be limiting. For example, certain termsmay be used such as “up,” “down,”, “upper,” “lower,” “horizontal,”“vertical,” “left,” “right,” and the like. Such terms are used, whereapplicable, to provide some clarity of description when dealing withrelative relationships, particularly with respect to the illustratedembodiments. Such terms are not, however, intended to imply absoluterelationships, positions, and/or orientations. For example, with respectto an object, an “upper” surface can become a “lower” surface simply byturning the object over. Nevertheless, it is still the same surface andthe object remains the same. As used herein, “and/or” means “and” or“or”, as well as “and” and “or.”

All patent and non-patent literature cited herein is hereby incorporatedby references in its entirety for all purposes. Incorporating theprinciples disclosed herein, it is possible to provide a wide variety ofsystems configured to render an electrosurgical handpiece inoperable ator near an end of the handpiece's safe useful life, in addition to thesystems described above.

The technologies from any example can be combined with the technologiesdescribed in any one or more of the other examples. Accordingly, thisdetailed description shall not be construed in a limiting sense, andfollowing a review of this disclosure, those of ordinary skill in theart will appreciate the wide variety of electrosurgical systems that canbe devised using the various concepts described herein. Moreover, thoseof ordinary skill in the art will appreciate that the exemplaryembodiments disclosed herein can be adapted to various configurationswithout departing from the disclosed principles. Thus, in view of themany possible embodiments to which the disclosed principles can beapplied, it should be recognized that the above-described embodimentsare only examples and should not be taken as limiting in scope.Therefore, I claim all that comes within the scope and spirit of thefollowing claims, and reserve the right to claim in the future any orall aspects of any innovation shown or described herein.

What is claimed is:
 1. A method for forming a directional mesh, themethod comprising the steps of: a) interweaving a first plurality ofwires wound in a first helical direction about a longitudinal axis witha second plurality of wires wound about the longitudinal axis in asecond, opposite helical direction to thereby provide the first andsecond plurality of wires extending from a proximal interwoven endsegment to a spaced apart distal interwoven end segment, wherein anoperative segment resides intermediate the proximal and distalinterwoven end segments, b) wherein with respect to an imaginary planealigned perpendicular to the longitudinal axis, the first and secondplurality of interwoven wires in the operative segment comprise a firstregion of relatively higher interwoven wire-density positionedcircumferentially spaced from a second region of relatively lowerinterwoven wire-density, and c) wherein the proximal and distalinterwoven end segments have the same number of wires, each as a sum ofthe first and second plurality of wires, and wherein the combined firstand second regions of relatively higher and lower interwovenwire-density in the operative segment have an equal number of wires asthe sum of the first and second plurality of wires in the respectiveproximal and distal interwoven end segments.
 2. The method of claim 1,including configuring the directional mesh so that applying acompressive load to at least one of the proximal and distal interwovenend segments causes the operative segment to deform into anasymmetrically-buckled configuration having the first region ofrelatively higher interwoven wire-density being spaced radiallyoutwardly further from the longitudinal axis than the second region ofrelatively lower interwoven wire-density.
 3. The method of claim 2,including configuring the directional mesh having a circular shape incross-section in a compact configuration without an axial force beingapplied to at least one of the proximal and distal interwoven endsegments toward the other end segment.
 4. The method of claim 1,including positioning the first region of relatively higher interwovenwire-density in the operative segment being circumferentially oppositethe second region of relatively lower interwoven wire-density.
 5. Themethod of claim 1, including providing a first wire-pitch of one or bothopposed proximal and distal interwoven end segments being greater than asecond wire-pitch in the operative segment.
 6. The method of claim 1,including providing the operative segment as a braided directional mesh.7. The method of claim 1, including providing each of the first andsecond plurality of wires extending helically around the longitudinalaxis at a pitch of from 120° to 240°.
 8. The method of claim 1,including configuring the directional mesh so that passing an electricalcurrent through the first and second plurality of interwoven wiresgenerates a plasma field in the operative segment.
 9. The method ofclaim 2, including varying a longitudinal pitch of the first and secondplurality of interwoven wires so that the proximal interwoven endsegment of the directional mesh has a corresponding first longitudinalpitch and the distal interwoven end segment of the directional mesh hasa corresponding second longitudinal pitch being relatively higher thanthe first longitudinal pitch.
 10. The method of claim 1, whereininterweaving the first plurality of wires with the second plurality ofwires comprises: a) orbiting a first plurality of wire carriers about anorbital center in a first orbital direction; and b) orbiting a secondplurality of wire carriers about the orbital center in a second orbitaldirection opposite the first orbital direction.
 11. The method of claim10, wherein at least one and fewer than all the first plurality of wirecarriers comprises a populated first wire carrier and at least one andfewer than all the second plurality of wire carriers comprise apopulated second wire carrier.
 12. The method of claim 11, wherein thepopulated first wire carrier comprises a first bobbin containing acorresponding first spool of wire, the first spool of wire constitutingthe first plurality of wires, and wherein the populated second wirecarrier comprises a second bobbin containing a corresponding secondspool of wire, the second spool of wire constituting the secondplurality of wires.
 13. The method of claim 1, including selecting thefirst and second plurality of wires from the group of stainless steel,copper beryllium, platinum, platinum iridium, a high-strength polymer,and combinations thereof.
 14. A method for forming an electricallyconductive woven construct, comprising the steps of: a) interweaving afirst plurality of electrically conductive wires wound in a firsthelical direction about a longitudinal axis with a second plurality ofelectrically conductive wires wound about the longitudinal axis in asecond, opposite helical direction to thereby provide the first andsecond plurality of electrically conductive wires extending from aproximal interwoven end segment providing a first electrode to a spacedapart distal interwoven end segment providing a second electrode,wherein an operative segment resides intermediate the proximal anddistal interwoven end segments, b) wherein with respect to an imaginaryplane aligned perpendicular to the longitudinal axis, the first andsecond plurality of interwoven electrically conductive wires in theoperative segment comprise a first region of relatively higherinterwoven wire-density positioned circumferentially spaced from asecond region of relatively lower interwoven wire-density, and c)wherein the proximal and distal interwoven end segments have the samenumber of electrically conductive wires, each as a sum of the first andsecond plurality of electrically conductive wires, and wherein thecombined first and second regions of relatively higher and lowerinterwoven wire-density in the operative segment have an equal number ofelectrically conductive wires as the sum of the first and secondplurality of wires in the respective proximal and distal interwoven endsegments.
 15. The method of claim 14, including configuring thedirectional mesh so that passing an electrical current through the firstand second plurality of interwoven electrically conductive wiresgenerates a plasma field in the operative segment.
 16. The method ofclaim 14, including configuring the directional mesh so that applying acompressive load to at least one of the proximal and distal interwovenend segments causes the operative segment to deform into anasymmetrically-buckled configuration having the first region ofrelatively higher interwoven wire-density being spaced radiallyoutwardly further from the longitudinal axis than the second region ofrelatively lower interwoven wire-density.
 17. The method of claim 14,including varying a longitudinal pitch of the first and second pluralityof interwoven wires so that the proximal interwoven end segment of thedirectional mesh has a corresponding first longitudinal pitch and thedistal interwoven end segment of the directional mesh has acorresponding second longitudinal pitch being relatively higher than thefirst longitudinal pitch.
 18. The method of claim 14, includingpositioning the first region of relatively higher interwovenwire-density in the operative segment being circumferentially oppositethe second region of relatively lower interwoven wire-density.
 19. Themethod of claim 14, including providing a first wire-pitch of one orboth opposed proximal and distal interwoven end segments being greaterthan a second wire-pitch in the operative segment.
 20. The method ofclaim 14, including providing the operative segment as a braideddirectional mesh.
 21. The method of claim 14, including providing eachof the first and second plurality of electrically conductive wiresextending helically around the longitudinal axis at a pitch of from 120°to 240°.
 22. The method of claim 14, including configuring thedirectional mesh having a circular shape in cross-section in a compactconfiguration without an axial force being applied to at least one ofthe proximal and distal interwoven end segments toward the other endsegment.
 23. The method of claim 14, including selecting the first andsecond plurality of wires from the group of stainless steel, copperberyllium, platinum, platinum iridium, a high-strength polymer, andcombinations thereof.
 24. A method for forming a woven construct,comprising the steps of: a) interweaving a first plurality of wires in afirst helical direction about a longitudinal axis at a pitch of from150° to 210° with a second plurality of wires wound about thelongitudinal axis in a second, opposite helical direction at a pitch offrom 150° to 210° to thereby provide the first and second plurality ofwires extending from a proximal interwoven end segment providing a firstelectrode to a spaced apart distal interwoven end segment providing asecond electrode, wherein an operative segment resides intermediate theproximal and distal interwoven end segments, b) wherein with respect toan imaginary plane aligned perpendicular to the longitudinal axis, thefirst and second plurality of interwoven wires in the operative segmentcomprise a first region of relatively higher interwoven wire-densitypositioned circumferentially spaced from a second region of relativelylower interwoven wire-density, and c) wherein the proximal and distalinterwoven end segments have the same number of wires, each as a sum ofthe first and second plurality of wires, and wherein the combined firstand second regions of relatively higher and lower interwovenwire-density have an equal number of wires as the sum of the first andsecond plurality of wires in the respective proximal and distalinterwoven end segments.